Gelcoat gurus, looking to get fancy

James331

James331

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James331
hey guys,

I'm looking at what I need to buy/read/do for my little 18' speed boat, so far planning on a soda blast and re gelcoat, looking todo it myself

Can I use normal pearl (house of kolors) in the gel coat?

What's the process for doing it? I don't have any gel coat experience, but I have every other week off and I'm looking to hit this thing like a 9-5.

Looking for white bottom paint (along the upper chime), transom and a thin racing stripe, red top and sides, quasi donzi style.

What am I looking at process and equipment wise.


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(Yes I'll shave the draggy nav light off and reupholster lol)

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House Of Kolor S2-KBC01 Shimirin 2 Candy Brandywine

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DP35 Deep Blue Dry Pearl
 
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It’s all in the prep work,if your going with a high end paint job,you don’t have to worry much about the gel coat.
 
frfly172 said:
It’s all in the prep work,if your going with a high end paint job,you don’t have to worry much about the gel coat.
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What about pearl IN the gel coat?


I know I can buff and paint over the existing gel, but taking it to bare glass and re gelcoating in said colors/pearls seems like the most proper way to go, no?
 
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James331 said:
no?
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No.

Gel coat is good stuff when you spray it into a female mold and then lay up the glass on top of it and then sell it to someone else. Otherwise not so much.

If you want to remove it, you will find that it's not a consistent thickness and blasting is not a precision process so removing it leaves you with a very uneven surface. Now, if the gel coat is cracking / crazing, you don't have much of a choice, but if it is solid, then you are setting yourself up for a lot of unnecessary work.

A lot.

Filling, sanding, sanding, sanding, filling, sanding, filling, sanding sanding sanding. And when you think you finally have it perfected, you will step back to admire your work, realize that it looks like crap, and go back to filling and sanding and sanding and sanding. Eventually you will come to hate the boat.

Also, a good paint will look nicer and last longer than gel coat.
 
Capt. Geoffrey Thorpe said:
No.

Gel coat is good stuff when you spray it into a female mold and then lay up the glass on top of it and then sell it to someone else. Otherwise not so much.

If you want to remove it, you will find that it's not a consistent thickness and blasting is not a precision process so removing it leaves you with a very uneven surface. Now, if the gel coat is cracking / crazing, you don't have much of a choice, but if it is solid, then you are setting yourself up for a lot of unnecessary work.

A lot.

Filling, sanding, sanding, sanding, filling, sanding, filling, sanding sanding sanding. And when you think you finally have it perfected, you will step back to admire your work, realize that it looks like crap, and go back to filling and sanding and sanding and sanding. Eventually you will come to hate the boat.

Also, a good paint will look nicer and last longer than gel coat.
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So on and off the trailer gel will last the same as pant?

Minus a few small spots the gel is structurally good on the boat.

This little boat isn't a flip, I'll be putting a good chunk of time and money into it.
 
James331 said:
So on and off the trailer gel will last the same as pant?

Minus a few small spots the gel is structurally good on the boat.

This little boat isn't a flip, I'll be putting a good chunk of time and money into it.
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If most of your gelcoat is good, repair the bad spots and go forward. As stated earlier in the thread, gelcoat is used as the first layer against the mold. It is largely a labor saving trick. Applying it out of the mold and fairing it to smooth is tough, particularly for large surfaces. Unless the boat is priceless and deserves tens, maybe hundreds of hours sanding and filling, repair the bad spots and move on.
 
kyleb said:
If most of your gelcoat is good, repair the bad spots and go forward. As stated earlier in the thread, gelcoat is used as the first layer against the mold. It is largely a labor saving trick. Applying it out of the mold and fairing it to smooth is tough, particularly for large surfaces. Unless the boat is priceless and deserves tens, maybe hundreds of hours sanding and filling, repair the bad spots and move on.
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Understood, budgeting 3k in materials and 100hrs of my time, what is the best method to use on this boat?

Seeing the finish I want
Paint or re gel?
 
I like that red. Sapphire blue metallic (Porsche color) would look awesome too.
 
James331 said:
Understood, budgeting 3k in materials and 100hrs of my time, what is the best method to use on this boat?

Seeing the finish I want
Paint or re gel?
Click to expand...

Me? I grind out the cracked/damaged portions of the gelcoat, skim with a microballoon/epoxy filler, block sand, epoxy coat to fill pinholes and leave a hard shell, sand again, and paint. That's how I've done all of the fiberglass stuff on a couple of airplanes.

But I'd ask in a boat forum. They probably know more about fixin' boats than I do.
 
kyleb said:
Me? I grind out the cracked/damaged portions of the gelcoat, skim with a microballoon/epoxy filler, block sand, epoxy coat to fill pinholes and leave a hard shell, sand again, and paint. That's how I've done all of the fiberglass stuff on a couple of airplanes.
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It's one thing to do 110kts in the air, another to do 75mph in the water and up on a trailer or sandbar, do you think paint would hold up?
 
It's been ages since I have done any gel-coat work. Gelcoat requires a special gun, they aren't cheap, It never goes on smooth, it always require sanding and polishing. Only tooling gelcoat gets really hard, so when you try to sand it balls up and clogs your sand paper, So you must sand wet, and a little soap in the water helps.
I hated working with the stuff, that's why It has been a long time since I did any thing with it.
 
You will find that the painted boats are usually cruisers larger than 30', and only the more expensive builders like Hatteras use it.

I have been boating for over 40 years, so make what you wish of my experience. I have painted boats and re-gelcoated them. On small boats gelcoat is much more durable than paint by a wide margin.

Small boats are off and on trailers and are pulled dockside much more often than the painted boats. In my experience, paint chips quite easily from dock bumps while gelcoat is more resilient and can be touched up easily.

Applying gelcoat is more labor intensive. It hardens with an orange peel surface, and must be sanded, cut, buffed, and polished. However, doing a boat the size of yours isn't a big deal.

I had to repair a small section of the gelcoat on the boat I earlier posted a photo of. Fortunately it was a standard HOK metalflake color (after 45 years!), and I just mixed the flake with clear gelcoat.

These guys have pearl products that can be mixed with gelcoat. There are probably others out there. Also, call HOK and see what they have to say.

https://www.paintwithpearl.com/fiberglass-surfboard-paint-kayak-paint/

Check out fibreglast.com for their line of refinishing gelcoats. They have some 900 colors to choose from, and they have a really helpful YouTube channel.

There are typical "how to" documents that can be found with a simple search.

You mentioned above soda blasting and removing the existing gelcoat down to the fiberglass. That's not necessary. Sand the existing gelcoat with 150 grit, use one of the typical spot repair compounds for dings and scratches, then prep and apply the new gelcoat.

Gelcoat can be applied with a cup gun and the proper sized tip, 2.0-2.5 mm is what I have used. Applied thickness should be 15-20 mils. Sand the finish with 250, 400, then 600. You can compound it at that point, or do additional sanding with 800.

The 3M Perfect It marine gelcoat finishing product line is the best I have found. They have prep, cut, and polish products. The abrasiveness of the compounds vary for differing applications.

This link is to a photo I took of my 1967 Howard after I sanded, cut, and polished the bare hull. The gelcoat was dull and tired, the boat hadn't been in the water since 1974. You can get results like this by reading and watching videos of how to apply new gelcoat.

https://www.flickr.com/photos/68961660@N05/38123257711/in/dateposted-public/

I used a forklift to slide the trailer out from under the boat and to flip it to do the bottom. It's not difficult.
 
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3393RP said:
You will find that the painted boats are usually cruisers larger than 30', and only the more expensive builders like Hatteras use it.

I have been boating for over 40 years, so make what you wish of my experience. I have painted boats and re-gelcoated them. On small boats gelcoat is much more durable than paint by a wide margin.

Small boats are off and on trailers and are pulled dockside much more often than the painted boats. In my experience, paint chips quite easily from dock bumps while gelcoat is more resilient and can be touched up easily.

Applying gelcoat is more labor intensive. It hardens with an orange peel surface, and must be sanded, cut, buffed, and polished. However, doing a boat the size of yours isn't a big deal.

I had to repair a small section of the gelcoat on the boat I earlier posted a photo of. Fortunately it was a standard HOK metalflake color (after 45 years!), and I just mixed the flake with clear gelcoat.

These guys have pearl products that can be mixed with gelcoat. There are probably others out there. Also, call HOK and see what they have to say.

https://www.paintwithpearl.com/fiberglass-surfboard-paint-kayak-paint/

Check out fibreglast.com for their line of refinishing gelcoats. They have some 900 colors to choose from, and they have a really helpful YouTube channel.

There are typical "how to" documents that can be found with a simple search.

You mentioned above soda blasting and removing the existing gelcoat down to the fiberglass. That's not necessary. Sand the existing gelcoat with 150 grit, use one of the typical spot repair compounds for dings and scratches, then prep and apply the new gelcoat.

Gelcoat can be applied with a cup gun and the proper sized tip, 2.0-2.5 mm is what I have used. Applied thickness should be 15-20 mils. Sand the finish with 250, 400, then 600. You can compound it at that point, or do additional sanding with 800.

The 3M Perfect It marine gelcoat finishing product line is the best I have found. They have prep, cut, and polish products. The abrasiveness of the compounds vary for differing applications.

This link is to a photo I took of my 1967 Howard after I sanded, cut, and polished the bare hull. The gelcoat was dull and tired, the boat hadn't been in the water since 1974. You can get results like this by reading and watching videos of how to apply new gelcoat.

https://www.flickr.com/photos/68961660@N05/38123257711/in/dateposted-public/

I used a forklift to slide the trailer out from under the boat and to flip it to do the bottom. It's not difficult.
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Thank you!


Beautiful boat BTW
 
One detail often left out is that most gelcoat is unwaxed so it never hardens on the surface. The wax is put in with the intention that it will float to the surface and seal it from the oxygen in the air. This allows the surface to cure as much as it will. Without the wax the polyester resin used in the gelcoat won't cure....its oxygen inhibited and the result is the crap that builds up on your sandpaper when you're trying to sand it smooth. I used to make molds and build all sorts of composite parts from airplanes to boats, drones and various other stuff. Polyester sucks other than its low cost and simple operation. Gelcoat was mostly intended for use where the surface you see is against the mold where it will properly cure and the exposed surface does't cure so that the first layer of resin and glass will adhere. Many layups are done in stages to prevent excess heat and shrinkage so this is an important consideration. Using waxed resin will mess up your bond between layers. Using waxed gelcoat makes it possible to sand the stuff but you need to wet sand and it will still take you a while to get the crap off the surface as it fills your sandpaper with goo.

Having said all that I will say the others who have suggested other paints are 100% right on. Don't regelcoat because you don't need to. You have a decent surface now and you won't if you blast it off. Even if there is crazing, cracking or spots of chalked gelcoat you can fix them easy and not waste money on fillers to do the whole boat and tons of time to sand it back to a nice surface. We used to use Imron on boats with great results. It is waterproof which gelcoat is not and it lasts a lot longer without the chalking and blistering problems that Gelcoat has. Gelcoat blisters because of its chemistry that makes it a perfect candidate for reverse osmosis. Its a permeable membrane that allows water in to replace uncured resin or catalyst resulting in blisters. This mostly affects boats that sit full time in the water but can be found in weekenders too. You can find info on all this on some of the boat sites or just googling gelcoat blisters.


Frank
 
Gelcoat blisters because of continuous immersion and neglect. A small lake boat that is trailered will almost never blister during its useful life.

Gelcoat isn't the best material? Why is it used on almost every recreational boat made?

I doubt James would apply gelcoat without the proper hardening mix. He has lots of resources to consult.
 
Just spray PVA on over the gelcoat to seal from the air and the surface will harden. This is how I handle repairs, never tried to shoot a whole boat.

I'd be tempted to sand a spot with 800 grit then hit it with rubbing compound and wax to see what the potential of the stuff on the boat is. I've seen some real miracles on older gelcoated boats bringing the original finish back.
 
3393RP said:
Why is it used on almost every recreational boat made?
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Cost. Manufacturing speed. If you are working with a female mold, it works great. But that's a whole different thing than trying to spray it on the outside of an already done been built boat.

I re-did a 26 foot sailboat from keel to masthead. Worst part of the job was trying to fair the surfaces where I had removed the gel coat. Painted everything above the waterline with Awlgrip - no muss, no fuss, looked great, never chipped. Didn't have to buff and polish every spring like most of the rest of the boats in the yard.
 
We used gelcoat on molded 15meter fiberglass/carbon gliders because it gave us a base to sand on that didn't involve weakening the structure through sanding fibers. It was cheap and disposable. The paint used on the glider was a non-gelcoat epoxy.

We used gelcoat on 9 meter windmill blades because it was cheap and could be spread with squeegies by mostly untrained labor. It bonded to polyester resin well and looked good....til it didn't

We used gelcoat on boats because it could be put in the mold to give a nice surface that the customer would like without spending any extra money.
Its cheap, its crap but it holds up well enough for the purpose on recreational boats that don't sit in the water all the time. As I noted previously blistering is primarily a problem with boats that sit in the water for a long time.

I'm not accusing anyone of not mixing the catalyst properly. The problem is in the chemistry and no one can mix the material good enough to fix that. 2% catalyst is really hard to mix with the other 98% of material evenly. Even poorly mixed it will harden but the chemistry issues are there whether you mix well or not.

PVA and wax do work for helping harden the surface. It makes sanding easier but not easy. You still have a goo layer either way. The bad part is that the pva and wax are both contaminants in the gelcoat. They both get into the material and can create voids and delaminations of the paint especially if you recoat later. A lot of guys use them pretty successfully but a lot have problems with them too.

Bottom line is, gelcoat is cheap, easy to use for molding parts, not so easy for recoating and so far it hasn't been outlawed like a lot of paints. Last time I looked Imron was $300 per gallon with the hardener at $90 per pint. Gelcoat was still around $40/gal and catalyst was included. This is in gallon quantities so bulk is cheaper. I don't know if you can even buy imron anymore...

You can repaint with whatever you want including gelcoat. I'm not the mom or the fun police, just trying to help out with some real world experience.

You must choose......


Frank
 
Eh, I have real world experience gelcoating a few boats, including a 32' and a 26' small cruiser. They turned out great.

I did have four guys helping me sand and buff, so perhaps I am minimizing the effort required.

In the end, the choice is up to the boat owner.
 
No advice on spraying gelcoat from me. My gelcoat on the '76 runabout still shines like new, with just an annual polish. However, it's a trailered boat and has somewhere in the neighborhood of 750hrs total run-time on it per the Hobbs. So whether gelcoat was a cheap option for manufacturing, it's stood the test of time for our uses.
 
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